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KVM: SEV: Set RESET GHCB MSR value during sev_es_init_vmcb()

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Set the RESET value for the GHCB "MSR" during sev_es_init_vmcb() instead
of sev_es_vcpu_reset() to allow for dropping sev_es_vcpu_reset() entirely.

Note, the call to sev_init_vmcb() from sev_migrate_from() also kinda sorta
emulates a RESET, but sev_migrate_from() immediately overwrites ghcb_gpa
with the source's current value, so whether or not stuffing the GHCB
version is correct/desirable is moot.

No functional change intended.

Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/r/20250819234833.3080255-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2025-08-19 16:48:31 -07:00
parent 3d4e882e34
commit baf6ed1772
1 changed files with 11 additions and 13 deletions
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24
arch/x86/kvm/svm/sev.c
View File

@ -4480,7 +4480,7 @@ void sev_vcpu_after_set_cpuid(struct vcpu_svm *svm)
vcpu->arch.reserved_gpa_bits &= ~(1UL << (best->ebx & 0x3f));
}
static void sev_es_init_vmcb(struct vcpu_svm *svm)
static void sev_es_init_vmcb(struct vcpu_svm *svm, bool init_event)
{
struct kvm_sev_info *sev = to_kvm_sev_info(svm->vcpu.kvm);
struct vmcb *vmcb = svm->vmcb01.ptr;
@ -4541,6 +4541,15 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
/* Can't intercept XSETBV, HV can't modify XCR0 directly */
svm_clr_intercept(svm, INTERCEPT_XSETBV);
/*
* Set the GHCB MSR value as per the GHCB specification when emulating
* vCPU RESET for an SEV-ES guest.
*/
if (!init_event)
set_ghcb_msr(svm, GHCB_MSR_SEV_INFO((__u64)sev->ghcb_version,
GHCB_VERSION_MIN,
sev_enc_bit));
}
void sev_init_vmcb(struct vcpu_svm *svm, bool init_event)
@ -4560,7 +4569,7 @@ void sev_init_vmcb(struct vcpu_svm *svm, bool init_event)
sev_snp_init_protected_guest_state(vcpu);
if (sev_es_guest(vcpu->kvm))
sev_es_init_vmcb(svm);
sev_es_init_vmcb(svm, init_event);
}
int sev_vcpu_create(struct kvm_vcpu *vcpu)
@ -4585,17 +4594,6 @@ int sev_vcpu_create(struct kvm_vcpu *vcpu)
void sev_es_vcpu_reset(struct vcpu_svm *svm)
{
struct kvm_vcpu *vcpu = &svm->vcpu;
struct kvm_sev_info *sev = to_kvm_sev_info(vcpu->kvm);
/*
* Set the GHCB MSR value as per the GHCB specification when emulating
* vCPU RESET for an SEV-ES guest.
*/
set_ghcb_msr(svm, GHCB_MSR_SEV_INFO((__u64)sev->ghcb_version,
GHCB_VERSION_MIN,
sev_enc_bit));
mutex_init(&svm->sev_es.snp_vmsa_mutex);
}